1. Field of the Invention
The present invention relates to beneficial body supports, and in particular, to supports having alternating elements.
2. Description of Related Art
Bedridden patients being treated in the hospital or at home can develop bedsores (decubiti) under certain conditions. The Braden Scale evaluates the risk of sores by scoring six categories: (1) The ability of the patient to respond meaningfully to pressure-related discomfort, which may decline as a result of sedation, a diminished level of consciousness, or a limited ability to feel pain. (2) The degree of exposure of the skin to moisture from perspiration, body fluids, etc. (3) The amount of physical activity performed by the patient. (4) The patient's ability to change and control body position. (5) The adequacy and quality of the patient's nutritional status. (6) How often the patient moves or must be moved in a way that causes friction and shear forces.
One of the prime contributors to skin breakdown that causes decubiti, is the build-up of moisture between the patient's skin and the bedding on which the patient is resting (Braden Scale).
Insensible water loss from a body is approximately 50 ml/hour (“Textbook of Medical Physiology” Guyton & Hall, 2000). When a patient is febrile, the amount of moisture exuded through the skin can increase dramatically. If the patient is also incontinent of bowel and/or bladder, more fluids are exuded and act to increase the damage of shear on skin, which promotes decubiti formation.
Existing hospital beds do not allow for free flow of air under the patient. One typically expensive model by Hill-Rom incorporates a mechanical flow of air but is predicated on existence of continual electrical power.
Keeping skin temperature down will also reduce the risk of decubiti. Unfortunately, known bedding systems do not incorporate effective features for reducing or moderating skin temperature.
The prediction of porosity or permeability of fabrics via theoretical models has proven somewhat frustrating (The Relationship Between Porosity and Air Permeability of Woven Textile Fabrics, Epps & Leonas, Journal of testing and Evaluation, Vol. 25, 1997, pp 108-113). Fortunately the measurement of air and moisture is not, and is available for the common fabrics (sheeting, print cloth, flannel, sateen, plain weave, batiste, poplin, and the synthetics: taffeta, challis, and plain weave triacetate).
Rather complicated beds are available for providing a body support that reduces the tendency for bedsores. These beds provide continually changing pressure points that prevent stasis. However, these beds are not widely available because their complexity and cost make them impractical for widespread use in most hospitals, as well as being beyond the financial reach of most home users. Moreover, these beds have many drawbacks in that they do not promote adequate air circulation around the patient, are not easily dismantled for set up or cleaning, cannot be easily operated manually during a power failure, etc.
In U.S. Pat. No. 5,083,551 three endless bands are looped around the seat of a wheelchair and are tightened and slackened by a single camshaft with three cam faces phased 120° apart.
In U.S. Pat. No. 4,155,592 straps 28 secured to the right edge of a seatback stretch across a frame from left to right and are routed past a camshaft 36. Rotation of camshaft 36 will selectively tighten some of the straps to adjust the lumbar support.
In U.S. Pat. No. 4,837,878 a bed is provided with stretchable straps alternating with non-stretchable straps. Strap tension can be adjusted mechanically, including by winding the strap around a rotatable shaft.
In U.S. Pat. No. 2,112,367 levers 35 on the right side of a bed frame attach to the right end of odd straps 29 while levers 35 on the left side attach to the left end of even straps. Levers on opposite sides are either moving toward or away from the middle to move the consecutive straps in opposite longitudinal directions.
In FIG. 32 of U.S. Pat. No. 5,862,550 a panel is slotted to provide a plurality of flexible bands, flexibility being enhanced by providing the U-shaped bands at 108 of FIG. 3. Cams on an underlying camshaft raise and lower alternate bands to avoid bedsores.
In U.S. Pat. No. 5,443,439 plates 11 can be tilted in different phases by a camshaft.
In U.S. Pat. No. 5,103,511 a sling-like cradle is automatically rocked back and forth to avoid bedsores.
In U.S. Pat. No. 4,459,712 a mesh can circulate on rollers 14,16, and 18. The height of roller 18 can be changed to adjust the sag in the top span of the mesh. See also U.S. Pat. No. 4,109,329.
In FIG. 5 of U.S. Pat. No. 5,109,558 a crank rocks levers 273 to vertically reciprocate the bed elements 205 to avoid bedsores. See also U.S. Pat. No. 5,626,555.
In U.S. Pat. Nos. 6,557,937 and 6,676,215 six slats form the seat of a wheelchair. A motor associated with each slat drives a crankshaft to vertically reciprocate its slat.
In U.S. Pat. No. 5,776,048 a burn patient lies on a row of fixed bars 38 interleaved with reciprocating bars 43. The reciprocating bars rise above and descend below the fixed bars to prevent bedsores. The bars have a removable core that can be removed for washing.
In U.S. Pat. No. 5,161,267 a patient is lifted by a number of parallel straps in order to change bed linens.
In U.S. Pat. No. 4,625,487 a number of transverse cushions are held in cradles to form a bed. Alternate cradles can be rocked in opposite directions to produce alternating lift points that can massage a person and prevent bedsores. See also U.S. Pat. No. 4,494,260 where cradled cushions are all rocked in the same direction.
In U.S. Pat. No. 3,464,406 a bed surface is supported by a number of parallel rods 100, each mounted between an opposite pair of planetary gears 90. The rods 100 are mounted eccentrically and at different phases so that when gears 9 are rotated, the rods produce a wave-like motion.
In FIG. 5 of U.S. Pat. No. 4,999,861 a bed surface is formed from a number of parallel slats 18 with rollers that ride on cams 64, which are phased to produce a wave-like motion. See also U.S. Pat. No. 4,202,326.
In U.S. Pat. No. 4,958,627 a bed is formed of a number of parallel wires 13. A motor-driven cam swings a lever 32 (FIG. 3) to periodically hit and lift the wires 13 as shown in the upper left portion of FIG. 2.
In U.S. Pat. No. 6,009,873 a pair of inflatable wedges are placed on opposite sides of a patient and held in place with encircling straps to maintain the patient's position.
In U.S. Pat. No. 4,769,864 a single, stationary bed frame is strung with a wire that crosses the bed multiple times in a serpentine path.
See also, U.S. Pat. Nos. 2,112,367; 5,233,712; 4,999,861; 5,659,910; and 5,626,555.
Accordingly, there is a need for an improved body support and method for supporting a body that can provide a beneficial effect, such as preventing bedsores.